(2S)-1-(tert-Butoxycarbonyl)-2-methylpyrrolidine-2-carboxylic acid

(S)-2-Methylpyrrolidine-2-carboxylic acid hydrochloride (23; 82.5 g, 498 mmol) is dissolved in a 1 / 1 -mixture of MeCN / water (1000 ml) and TEA (210 ml; 1490 mmol) is added followed by the addition of BocTo a stirred solution of (S)-2-methylpyrrolidine-2-carboxylic acid (0.42 g, 3.25 mmol) and BOCExample 8 2) Synthesis of (S)-1-(tert-butoxycarbonyl)-2-methylpyrrolidine-2-carboxylic acid2-Methyl-L-proline hydrochloride (99.7 g; 602 mmol) is dissolved in a i/i-mixture of MeCN and water (800 ml) and triethylamine (254 ml; 1810 mmol) is added. The temperature of the reaction mixture slightly rises. The reaction mixture is cooled to 10°C to 15°C followed by careful addition of a solution of Boc2O (145 g; 662 mmol) in MeCN (200 ml) over 10 minutes.Stirring at RT is continued for 2 hours. The MeCN is evaporated under reduced pressure and aq. NaOH solution (2M; 250 ml) is added to the residual aq. part of the reaction mixture. The water layer is washed with Et20 (2x 300 ml) then cooled to 0°C followed by slow and careful addition of aq. HCI (25percent) to adjust the pH to 2. During this procedure a suspension forms. The precipitate is filtered off and dried at HV to give 110.9 g of the title compound as a beigepowder; tR [mm] = 0.68; [M+H] = 230.14.[0657] To a solution of 2S-methyl-pyrrolidine-2-carboxylic acid hydrobromide (1.50 g, 11.6 mmol; Bachem) in a mixture of H2O (15 ml) and dioxane (15 ml) was added Et3N (3.6 ml, 26 mmol) and di-tert-butyl dicarbonate (5.57 g, 25.5 mmol). The resultant solution stirred for 5 h, diluted with H2O (50 ml), washed with Et2O (50 ml), acidified to pH 2 with 10percent HCl, and extracted with 10percent MeOH/CHCl3 (2.x.100 ml). The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo to afford 1.1 g of white powder in 64percent yield, which displayed an 1H NMR that matched previously reported (Khalil, et al., Tetrahedron Lett., 37, 3441-3444 (1996)) and was used without any further purification.2-Methyl-L-proline hydrochloride (99.7 g; 602 mmol) is dissolved in a i/i-mixture of MeCN and water (800 ml) and triethylamine (254 ml; 1810 mmol) is added. The temperature of the reaction mixture slightly rises. The reaction mixture is cooled to 10°C to 15°C followed by careful addition of a solution of Boc2O (145 g; 662 mmol) in MeCN (200 ml) over 10 minutes. Stirring at RT is continued for 2 hours. The MeCN is evaporated under reduced pressure andaq. NaOH solution (2M; 250 ml) is added to the residual aq. part of the reaction mixture. The water layer is washed with Et20 (2x 300 ml) then cooled to 0°C followed by slow and careful addition of aq. HCI (25percent) to adjust the pH to 2. During this procedure a suspension forms. The precipitate is filtered off and dried at HV to give 110.9 g of the title compound as a beige powder; tR [mm] = 0.68; [M+H] = 230.14

Molecular Weight:229.27
XLogP3:1.4
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:3
Exact Mass:229.13140809
Monoisotopic Mass:229.13140809
Topological Polar Surface Area:66.8
Heavy Atom Count:16
Complexity:308
Defined Atom Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes